The AFLP technique was used to analyze the genetic diversity of 4 different generation groups of Litopenaeus vannamei,which were primary parent,F₁ generation,F₂ generation and F_n generation.10 pair AFLP selective primer scanned 20 samples from each generation and 483 loci were amplified,348 loci were polymorphic loci.The proportions of polymorphic loci among the 4 generation samples were 61.90%, 49.28%, 50.52% and 46.38% respectively.The genetic diversities of the 4 different generations quantified by Shannon index were 0.313 4,0.262 1,0.259 4 and 0.226 2 respectively.The result shows that the genetic distance between primary parent and F₁ generation sample is closer than that between F₂ and F_n generation samples.The research of genetic diversity among 4 different generations could provide theoretical support for future study on hybrid selective breeding.